Question: Was this man incompetent?

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No, seriously.  How would you describe Ambrose Burnside’s generalship?

What words would you chose to describe him?

Where I’m going with this – what is at the heart of the “ratings” we often give to a general and his performance?  Burnside just happens to be a handy target example to select, given the upcoming Antietam anniversary. I could just as easily select this fellow and ask the same question:

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How about Henry W. Slocum?  What words come to mind when rating his military career?

Fortification Friday: Let’s put some platforms beneath the cannons!

In the most recent installments of Fortification Friday, we’ve looked at the ways to mount artillery in the fortification, according to Mahan’s instructions.  These methods involved barbette batteries, firing over the parapet, and embrasures, allowing the guns to fire through the parapet.  One more detail need be discussed in regard to placement of the guns – the actual surface on to which the guns sat.  We’ve touched upon this to an extent by identifying the mound used for barbettes (and sometimes for embrasures where the parapet is tall).  And we’ve defined the area required to allow for recoil of the gun.  But we have not taken into account the effects of that recoil on the mound or earth where the gun is placed.  In order to prevent damage to the fortification, the area detailed for the gun needed strengthening.

And that strengthening was called a platform.  So let us pick up with Mahan:

Platforms.  When a gun is fired often in the same direction, the ground under the wheels is soon warn into ruts; it is to prevent this, that platforms of timber are used in such cases.

Sometimes I will slip-up and refer to the mound of the barbette as the platform, as it does somewhat function as a platform under Webster’s definition.  But strictly speaking, if we are talking forts, then we work with Mahan’s definition. And Mahan said specifically that platforms are the timber support placed under the gun’s firing position.

From that, Mahan explained the preferred arrangement of the platform:

The shape of the platform is usually a rectangle; in some cases, where a wide field of fire is to be obtained, the form is a trapezoid. The rectangular platform is ten feet wide, and seventeen feet long, for siege pieces; and nine feet wide and fifteen feet long, for field guns.  It consists of three sleepers of six inch scantling, either fiften or seventeen feet long, which are laid perpendicular to the direction of the epaulment, and are covered with two-inch plank, twelve inches wide, and cut into lengths of nine or ten feet.  Between the ends of the sleepers, and the foot of the genouillére, a piece of eight-inch scantling, nine feet long, termed a heurter, is laid; it should project about six inches above the platform, and be bisected by the directrix.  The object of the heurter is to prevent the wheels from being run against the revetment, and also to give the gun its proper direction, particularly in night firing.

So let’s turn to the figures to illustrate how this looked:

PlateIVFig33bisPlatformA

This is a sub-section of Figure 33 bis, which we used when discussing the construction of embrasures.    We are provided a view from above (on the right) and another from the side (to the left).  This platform is for an oblique embrasure, and thus oriented based on a directrix angled to the right-front of the parapet.  Breaking this down by parts:

PlateIVFig33bisPlatformB

I’ve outlined the three sleepers in red – six inch square timbers, fifteen to seventeen feet long.  Just one of the planks is outlined (in gold color), for simplicity.  Those were two inch thick, twelve inch wide, and nine to ten feet long.  Lastly there is the heurter in green – eight inch square and nine feet long.  Note how the heurter is not as wide as the planks.

The dimensions of the platform were larger than the actual footprint of the gun itself so as to allow the crew better footing, and to be at the same level as the gun they were servicing.

Notice the position of the heurter in the diagram.  As Mahan stated, this position prevented the gun from rolling forward into the works.  And it also gave the crew a fixture to “square” the gun when placed into battery for firing.  Off that, the gun might be oriented off the directrix to suit the necessary traverse, and elevation, as needed.  I’ve seen mention of stakes or other marks used by the crews to facilitate rapid orientation of the gun on certain targets. Say like having a mark on the platform indicating the orientation (and perhaps even the elevation) to aim at a ditch just off the directrix.  Old school “registration” of fires, if you wish.

Mahan continued with instructions for building the platform:

To lay a platform, the earth on which it is to rest should be well rammed and leveled; three trenches are then made for the sleepers, two of which should be placed under the wheels, and the middle one under the trail.  The sleepers are laid flush with the ground, and firmly secured by pickets driven at their sides and ends, and the earth is solidly packed in the trench around them; the plank is then laid and secured by nails, or some other fastenings.

Notice the sleepers are placed in trenches and actually lay close to, if not at, ground level.  This ensured the planks were not raised significantly above ground, and thus would not become a hazard during action.  Nothing more embarrassing than having the powder monkey trip over an exposed plank or sleeper!

And should the platform be level all around?

If the platform is for direct firing, with full charges, the tail may be six inches higher than the front to break the recoil; in all other chases it should be horizontal.

So for certain arrangements, a nice slope to arrest the recoil of the gun was specified.

Mahan also offered a plan for simplifying the platform if necessary:

A platform may be constructed simply of three pieces of timber, one under each wheel, and one under the trail, firmly secured by pickets, and connected by cross pieces, into which they are halved.

Illustrated as such:

PlateIVFig32E

Such was probably best used for embrasures with very limited range of traverse.  With a wide traverse, more surface area would be needed.

Of course, that brings up question about arranging for barbettes where a wide traverse was desired:

For barbettes, the platform may be dispensed with; or, if used, the whole surface nearly of the barbette should be covered.

So if you didn’t want to waste the timber, the barbettes wouldn’t need one.  From wartime photos, we see barbettes with and without platforms.  And where used with a barbette, a trapezoidal, verses the square, platoform was more likely:

If the platform is made of a trapezoidal form, it will require five sleepers.

No illustration of this was offered.  But likely these sleepers were angled off the outside pair, to provide support for planks running further out at the rear of the platform.  And there was no set layout for placing planks across those sleepers.  Thus we are left to assume some common sense and practical experience dictated the arrangement from there.

(Citations from Dennis Hart Mahan, A Treatise on Field Fortifications, New York: John Wiley, 1852, pages 56-8.)

 

 

On this day… September 7, 1863 -Charleston learns Morris Island lost

Robert Moore ran a couple of “on this day” posts earlier, looking back at reports in Shenandoah newspapers.  After spending most of the sesquicentennial with “on this day” writing, I’ve gotten out of habit for the most part.  But I retain the historical mindset when looking at the calendar. So occasionally I’ll link to an old post on Facebook or Twitter as a way of mentioning anniversary dates.

But Robert’s use of newspaper accounts reminds me of the veritable mountain of source material that I’ve accumulated over the years when studying the war at Charleston, South Carolina.  And September 7 is an important anniversary date.  On that date in 1863 Morris Island was evacuated marking the end of a long Federal campaign to secure that barrier island outside Charleston.  Readers will recall the many posts about that campaign during the sesquicentennial.  I detailed the last three days of the campaign at that time.  On September 5, under protection of a withering bombardment, the Federal sap advanced towards Battery Wagner – just fifty yards short at around midnight.  The following day, Federals prepared to make a final assault, developing footholds just 100 feet from the battery parapet by 10 PM that evening. However, that final assault would not be necessary.  Overnight, the Confederate garrison withdrew, leaving Morris Island to the Federals.

Using that story (detailed in the links above), let’s step back and think of another perspective.  How did the citizens of Charleston, the Confederate “home front” so close to the fighting front, receive this news?

Granted, many could simply look across the harbor at Morris Island and Fort Sumter.  And the sound of cannons likely echoed into the streets at times (not to mention shells fired at Charleston itself, as way of showing the war was not very distant).  And of course there were always rumors and gossip spreading news. But for the “factual” news, Charleston had two primary newspapers – the Charleston Mercury and the Charleston Daily Courier.  I have reason to believe the Courier was a morning paper, while the Mercury was afternoon or evening. Perhaps confirming that cycle, the Mercury was able to break the news of Morris Island’s evacuation on September 7, 1863 (on the second page):

Evacuation of Morris Island

To sum up the events through which we have just passed, Battery Wagner has been subjected during the last three days and nights to the most terrific fire that any earthwork has undergone in all the annals of warfare.  The immense descending force of the enormous Parrott and mortar shells of the enemy had nearly laid the wood work of the bombproofs entirely bare, and had displaced the sand to so great a degree that the sally-ports are almost entirely blocked up. The parallels of the enemy yesterday afternoon had been pushed up to the very mouth of Battery Wagner, and it was no longer possible to distinguish our fire from that of the enemy.  During the entire afternoon the enemy shelled the sand hills in the rear of Battery Wagner (where our wounded lay) very vigorously.

Under these circumstances, and in view of the difficulties of communication with Cumming’s Point, the impossibility of longer holding Morris Island became apparent, and it was determined that strenuous efforts should be made at once to release the brave garrison of the Island, who seemed to be almost within the enemy’s grasp.  This desirable result was accomplished with the most commendable promptitude and success.

At about six o’clock, yesterday afternoon, the orders for the evacuation were delivered to Col. Keitt, commanding our forces on the island. Everything was at once made ready for the abandonment of Batteries Wagner and Gregg.  The dead were buried, and, at nightfall, the wounded were carefully removed in barges to Fort Johnson.  The guns, which, for so many weeks had held the foe at bay, were double-shotted, fired and spiked; the heavier pieces were dismounted, and the carriages rendered worthless. The preliminary preparations being thus completed, the work of embarkation was noiselessly begun, and the brave men of the garrison, in forty barges, were soon gliding from the beach they had held so stoutly and so long.  The evacuation was conducted by Col. Keitt, assisted by Major Bryan A.A.G.; and the success with which what has always been considered one of the most difficult feats of warfare has been performed is worthy of the highest praise.  Batteries Gregg and Wagner had both been carefully mined, with a view to blowing them up.  It was about one o’clock this morning when the last three boats – containing Col. Keitt and a number of his officers – left the island. The slow match was lighted by Captain Huguenin at Wagner, and by Captain Lesesne at Gregg; but, owing to some defect in the fuses, no explosion took place at either fort.

During the evacuation the enemy was not idle. A constant fire of shell was kept up against Wagner, and his howitzer barges were busily plying about this side of Morris Island, to prevent the retreat of our men. But fortunately the night was murky, and all our barges,with the exception of one, containing twelve or fifteen men, passed in safely.

Such is how the residents of Charleston learned of the loss of Morris Island on the evening of September 7, 1863.  Notice the narrative put some, not so unexpected, spin on the events.  In some ways to save face, to be sure.  At the same time to let readers know the Confederate soldiers had fought well and endured much.  A retreat could be justified with honor.

When we look back at this, knowing more so the 360° panorama of history, might offer more details to the story.  Certainly it is significant that US Colored Troops were at the fore of those efforts to take Battery Wagner.  Did the reporters for the Mercury know that? And did the residents of Charleston (white and black) know that?  I have a feeling the deeds of the USCT were indeed known, if not reported.  And we might imply some spin from just that alone.

Regardless, on this day in 1863 the residents of Charleston witnessed a grim turn in the war occurring at the mouth of their harbor.  Not surprisingly, on the second column of the first page ran a story, what we’d call today an op-ed piece, titled, “The Fate of Charleston if Captured.”

(Citation from Charleston Mercury, Monday, September 7, 1863, page 2, column 2.)

 

Summary Statement, 1st Quarter, 1863 – New Hampshire and New Jersey Batteries

The next set of entries in the first quarter, 1863 summaries cover volunteer batteries from the states of New Hampshire and New Jersey.  New Hampshire provided one light battery during the war.  And that is listed for the quarter.  New Jersey had only provided two such batteries up to that time (but three others were to form later).  So for these two states there are three entry lines:

0124_1_Snip_NH_NJ

For the New Hampshire battery:

  • 1st Battery: At Belle Plain, Virginia with six 3-inch Ordnance Rifles.  Captain Frederick M. Edgell’s battery was in First Division, First Corps, Army of the Potomac.

And for the two New Jersey batteries:

  • Battery A: White Oak Church, Virginia with six 10-pdr Parrotts.  The battery supported First Division, Sixth Corps. When Captain William Hexamer fell ill during the winter, Lieutenant Augustine N. Parsons assumed command of the battery.
  • Battery B: Potomac Creek, Virginia with six 10-pdr Parrotts. In January 1863, Captain A.Judson Clark commanded this battery, assigned to Second Division, Third Corps.  During the winter, the battery transferred to First Division of the corps.  When Clark took command of the artillery brigade in that formation, Lieutenant Robert Sims held command of the battery.

No surprises with the administrative details.  And we see only rifled guns were on hand with these three batteries. Thus we draw a blank page when looking at smoothbore ammunition:

0126_1_Snip_NH_NJ

Turning to the rifled projectiles, only the New Hampshire battery reported Hotchkiss-patent types:

0126_2_Snip_NH_NJ

  • 1st New Hampshire: 126 canister, 182 percussion shell, 538 fuse shell, and 360 bullet shell for 3-inch rifle.

On the next page, we can narrow the focus down to just Parrott-patent and Schenkl-patent entries:

0127_1_Snip_NH_NJ

And those are only for the New Jersey batteries:

  • Battery A, New Jersey: 530 shell, 360 case, and 134 canister of Parrott patent for 10-pdr Parrott.  And 70 shot of Schenkl-patent for the same 10-pdr Parrotts.
  • Battery B, New Jersey:  380 shell, 340 case, and 146 canister of Parrott patent for 10-pdr Parrott.

Continuing with Schenkl columns on the next page:

0127_2_Snip_NH_NJ

  • Battery B, New Jersey: 360 Schenkl shell for 10-pdr Parrott.

I would call attention to the types of projectiles reported here.  In this case, we have three batteries which are part of the main field army of the Eastern Theater.  One would assume these were well supplied.  And we see healthy quantities of shell, case, and canister.  But only one battery reported bolt or solid shot.  Yet, we know the leaders in the artillery formation of that army – namely Brigadier-General Henry Hunt – expressed a preference for the use of solid shot.

What would explain a shortage of solid shot?  Perhaps we are seeing the gap between intentions and the capabilities of the logistic system.  And perhaps extending that gap was the higher use, based on the chief’s instructions, of solid projectiles.  But short of some complaint by, say Hunt, to the Ordnance Department, there is no direct evidence to blame this on the supply system.  As with much in the summaries, we have numbers. And numbers are figures, yet not necessarily information.

And to close, we look at the small arms:

0127_3_Snip_NH_NJ

By battery:

  • 1st New Hampshire: Twenty-nine Navy revolvers and nine cavalry sabers.
  • Battery A, New Jersey: Fifteen Army revolvers and twenty-seven horse artillery sabers.
  • Battery B, New Jersey: Eighteen Navy revolvers and sixteen horse artillery sabers.

Of note, in the last quarter Hexamer’s Battery reported over a hundred sabers. Over the winter, the battery lost many of those – presumably turned in as unnecessary.

Fortification Friday: Direct and Oblique Embrasures

Last Friday we introduced the embrasure and identified the components of that structure.  In brief, the embrasure allowed the defender to place artillery so as to fire through the parapet instead of over it, thus granting the gunners some protection.  However, the nature of the embrasure limited the field of fire for the cannon.  Thus the directrix, bisecting the sole and thereby setting the cannon’s orientation, becomes an important line when setting up embrasures.

The lay of the directrix would determine what the cannon could point at.  And it was possible that the directrix be arranged with off-set angles to allow the cannon to fire with the desired effects:

When the directrix is perpendicular to the direction of the parapet, the embrasure is termed direct; when the directrix makes an acute angle with it the embrasure is termed oblique.

Those two types were demonstrated by Mahan in Figure 33 Bis:

PlateIVFig33bisDirectObliqe

I’ve highlighted the directrix of the direct embrasure in blue.  That of the oblique embrasure is in red, on the right. Obviously, the change in the angle would bring about refinements to the manner of construction of the embrasure.  And Mahan detailed those:

The manner of laying out an oblique embrasure is similar to the direct; the mouth is of a rectangular form, but is made wider in proportion to the obliquity, in order that the pat of the embrasure, which corresponds to the muzzle of the gun may be nearly of the same width in both the direct and oblique embrasures.  The exterior width of the sole is made equal to one half the length of the directrix, measured on the sole.  The cheeks are laid out as in the last case.

Allow me to use all colors to best illustrate what the professor is calling for here:

PlateIVFig33bisObliqe

A color explosion!  Yes, so we can call out specific lines for reference. First we have the mouth of the embrasure in green.  As suggested, this is nearly the same as on a direct embrasure.  But it is wider to the inside of the angle, to allow clearance of the muzzle.  And where it needs to be wider is on the exterior end of the box that is the mouth.

Take the measure of the directrix and apply half to the exterior end of the sole, the gold line above. As the angle of the dirextrix in this example is only slightly off perpendicular, we see the left side of the sole, and the corresponding cheek, are not far off the direct embrasure arrangements (outlined in yellow).

But it is on the right, on the inside of the angle, that adjustments are made. A line from the exterior of the sole back to the mouth has to cross outside the exterior of the mouth to reach the back of the interior (dashed blue line).  Thus the portion of what would have been the cheek (in red) must be cleared back.  And the right-side cheek must have a different interior point.  That adjustment is depicted with the solid blue line.

In short, a little geometry in order to ensure the projectile clears the embrasure without obstructions.

Such modifications, where applied, bring us to one limitation of the embrasure:

The muzzle of the gun should enter at least six inches into the embrasure, to prevent the blast from injuring the cheeks; this limits the obliquity of the directix to about 60° for long guns.

Thus, not only is the traverse of the gun limited by the embrasure, the line of fire possible from the gun has a limit.  No 59° oblique embrasures… definitely no 45° oblique embrasures.  For locations requiring fires at those angles from the parapet, a barbette was required.

And considering the force of the cannon’s discharge, another limiting factor comes into play:

The height of the cheeks must not be more than four feet, for the same reason; it will, therefore, in some cases, be necessary to raise the ground on which the wheels rest.

Common sense in play here – the deeper the sole of the embrasure is set, the more contained the force of the cannon’s blast.  And if contained too much, the force is apt to cause damage to the embrasure… or worse, to the parapet.  And to avoid a deep embrasure, Mahan suggested a mound or platform just as used with the barbette. Though obviously not as high.

These limitations defined, Mahan proceeded to introduce new terms defining components outside the embrasure itself:

The parapet of a battery is usually termed the epaulment. The interior face of the epaulment, and the cheeks of the embrasures, are [reveted] in the usual manner. That part of the interior face which lies below the chase of the gun is termed the genouillére. The mass of earth between two embrasures is termed a merlon.

The most important term to note here is epaulment, technically just indicating an altered parapet.  At times we see Civil War reports referring to epaulments and including parapets to the flanks of detached batteries. Even where one might think “traverse” would be an apt name to apply. In that general sense, epaulment was applied to the entire parapet constructed to protect the gun or guns.

As to constructing epaulments with embrasures?

The embrasures are generally cut out after the epaulment is thrown up. If their position is decided upon beforehand, they may be roughly formed at first, and be finished after the epaulment is made.

So you can just build a parapet, then clear out the embrasure later to create the epaulment.  Or one might save some earth moving and leave the intended embrasure clear while piling up the parapet/epaulment.  Results may vary.

One last word on embrasures – their advantages and best use:

The advantages of embrasures are, that the men and the guns are less exposed than in a barbette battery.  Their principal defects are, that they have a very limited field of fire; they weaken the parapet; and present openings through which the enemy may penetrate in an assault. Owing to their limited field of fire, they are chiefly used for the protection of particular points; as to flank a ditch, protect a salient, enfilade a road, &c. The most suitable position for them in a work is on the flanks.

This passage is important for historians to consider.  We see lots and lots of embrasures on surviving field fortifications.  Some of them, such as at Petersburg, are on besieging fortifications, where directrix would be defined so as to bring fire on specific points.  At the same time, Confederate fortifications at Petersburg have embrasures oriented so as to bring counter-fire on specific sections of the besieging lines.  Those pass a “form follows function” logic.

But on the other hand, there are many surviving defensive fortifications not associated with siege operations that don’t fall in line with Mahan’s suggested employment of embrasures.  Fort Evans, just a few blocks from where I’m writing this post, comes to mind.

Fort Evans 004

These embrasures were placed on a curtain wall, with dirextrix oriented across the face of the fortification.  Not a particular point, a salient, a flank, or to enfilade a road (though Edwards Ferry Road is nearby, the angle and separation work against that idea).

So why did the engineer make embrasures?

Well first off, the engineer most closely associated with the fort, John Morris Wampler, did not benefit from tutelage under Mahan at West Point.  Wampler was a trained topographical engineer, with experience surveying the coasts.  All indications are his military engineering skills were learned “on the job site.”  And this was his first major project. Not to detract from Wampler’s engineering skills (as he would later be involved with some rather good works around Charleston in particular).  But he built the works according to requirements set down by superiors.

Which brings us to another line of inquiry here – what did the Confederate commander want to do with those guns?  Well if one looks at the orientation of the embrasures, guns on that particular wall were oriented to fire over the Potomac River to the Maryland side of Edwards Ferry.  And embrasures on the north side of the fort were oriented at Ball’s Bluff, Harrison Island, and points beyond on the Maryland shore.

During the time Wampler and other Confederates built Fort Evans, their batteries faced off against Federal rifled batteries north of the Potomac.  While the Confederates had some rifled guns, the Federals at this time employed Parrott rifles (up to 30-pdrs).  Given the nature of the situation, embrasures were probably justified in order to best protect the gunners.  But, as with so much about Fort Evans, we don’t know that for sure.  Just offering some “form should follow function” logic.

(Citations from Dennis Hart Mahan, A Treatise on Field Fortifications, New York: John Wiley, 1852, pages 55-6.)

Summary Statement, 1st Quarter, 1863 – Massachusetts Batteries

Keeping strictly to the order presented in the summaries, the next state’s volunteer batteries to consider are from Massachusetts:

0124_1_Snip_MA

At first glance, this looks “clean” compared to the respective sections from western states.  Twelve numbered batteries, with nine reporting, and no lines for sections attached to cavalry or infantry.  But there are still kinks to work out and questions to ask:

  • 1st Battery: White Oak Church, Virginia.  Six 12-pdr Napoleons.  The battery was assigned to First Division, Sixth Corps, Army of the Potomac. Captain William H. McCartney commanded.
  • 2nd Battery: No return.  Captain Ormand F. Nims commanded this battery, assigned to the Fourth Division, Nineteenth Corps, Department of the Gulf.  As of January 1863, the battery reported six 6-pdr rifled field guns (if strictly interpreted, 3.67-inch caliber, but 3.80-inch sometimes were identified as such). Reports indicate the battery’s duty station was Baton Rouge, Louisiana.
  • 3rd Battery: Falmouth, Virginia with six 12-pdr Napoleons (corrected from the previous quarter’s return… see 5th Battery below). Assigned to the First Division, Fifth Corps and under Captain Augustus Martin.
  • 4th Battery: At Baton Rouge, Louisiana with four 12-pdr Napoleons and two 3-inch steel rifles. This battery was assigned to the Third Division, Nineteenth Corps, under Captain George G. Trull (though Lieutenant Joseph B. Briggs was temporarily in command during part of the winter).  The nature of the 3-inch rifles is a question for me.  With Sawyer and Wiard weapons of that caliber associated (by presence of surviving examples) with Massachusetts, but no direct citations at my grasp, I’ll leave full identification open.
  • 5th Battery: At Falmouth, Virginia with six 3-inch rifles.  Also assigned to 1st Division, Fifth Corps. The battery was under Captain Charles A. Phillips. The previous quarter, this battery supposedly had six 12-pdr Napoleons.  I think this a mix-up between the 3rd and 5th Batteries by the clerks, being corrected here in the first quarter of 1863.
  • 6th Battery: No return.  The battery was assigned to First Division, Nineteenth Corps, under Lieutenant William W. Carruth, with four 6-pdr Sawyer guns and two 12-pdr howitzers.
  • 7th Battery: Suffolk, Virginia with six 3-inch Ordnance rifles.  Assigned to the Seventh Army Corps, commanded by Captain Phineas A. Davis.
  • 8th Battery: No return.  Mustered out the previous November at the end of a six-month enlistment.
  • 9th Battery: Fort Ramsay, Virginia.  Six 12-pdr Napoleons.  The battery was part of the defenses of Washington.  The 9th Battery Light Artillery was part of Abercrombie’s Division with Lieutenants Charles Erickson and later John Bigelow, commanding.  Of course, we know the battery went on to some renown for action later in the year.
  • 10th Battery:  Poolesville, Maryland with six 3-inch Ordnance Rifles. The battery was assigned to the defenses of Washington, assigned to the Corps of Observation.  Captain J. Henry Sleeper commanded.
  • 11th Battery: Centreville, Virginia with six 3-inch Ordnance Rifles.  Also part of Washington’s defenses. This battery was assigned to Casey’s Provisional Division and commanded by Captain Edward J. Jones..
  • 12th Battery:  At New Orleans, Louisiana, with an annotation, “Stores turned over March 27 to…” a Lieutenant who’s name is illegible to me. Lieutenant Edwin M. Chamberlin commanded this battery of unattached artillery in the Nineteenth Corps. The battery arrived in Louisiana that winter and performed garrison and guard duties through the winter and early spring.

Turning now to the ammunition reported with the smoothbore types first:

0126_1_Snip_MA

Four batteries reporting, all of the same caliber:

  • 1st Battery: 396 shot, 74 shell, 251 case, and 131 canister for 12-pdr Napoleon.
  • 3rd Battery: 192 shot, 96 shell, 387 case, and 96 canister for 12-pdr Napoleon.
  • 4th Battery: 136 shot, 64 shell, 264 case, and 112 canister for 12-pdr Napoleon.
  • 9th Battery: 272 shot, 242 shell, 191 case, and 191 canister for 12-pdr Napoleon.

Of note, in each battery were were always more shot than canister.  And on most reporting lines more shell and case. While there are more canister on hand than one might expect, the majority of the rounds on hand reflected the tactical preference for artillery use.  I often wonder if the reported quantities of canister reflected some “over stock” due to the issue process.  As issue was often by chest (akin to what modern armies do with a “unit of fire”), there may have been a portion of unused canister retained.

Moving to rifled projectiles, we again find just one caliber to deal with.  And when turning to the Hotchkiss projectiles, we find five batteries reporting:

0126_2_Snip_MA

For those 3-inch rifles (be they standard Ordnance or otherwise):

  • 4th Battery: 40 canister, 240 percussion shell, and 120 fuse shell for 3-inch rifle.
  • 5th Battery: 80 canister, 120 percussion shell, 413 fuse shell and 540 bullet shell for 3-inch rifle.
  • 7th Battery: 205 canister, 198 percussion shell, 284 fuse shell, and 750 bullet shell for 3-inch rifle.
  • 10th Battery: 123 canister, 110 percussion shell, 240 fuse shell and 760 bullet shell for 3-inch rifle.
  • 11th Battery:  117 canister, 512 percussion shell, and 575 bullet shell for 3-inch rifle.

We are able to skip the next page of rifled projectiles as there were no Dyer’s, James’, or Parrott’s on hand.  Turning to the Schenkl columns:

0127_2_Snip_MA

A couple of lines:

  • 5th Battery: 80 Schenkl canister for 3-inch rifles.
  • 10th Battery: 15 Schenkl shell for 3-inch rifles.

Thus by a wide margin the Massachusetts artillerists had Hotchkiss projectiles for the first quarter.

Lastly, the small arms:

0127_3_Snip_MA

By battery:

  • 1st Battery: Thirteen Army revolvers, twelve cavalry sabers, and seven horse artillery sabers.
  • 3rd Battery: Twelve Army revolvers, eight cavalry sabers, and twenty-four horse artillery sabers.
  • 4th Battery: One .54 caliber carbine, seven Army revolvers, and forty-two horse artillery sabers.
  • 5th Battery: Six Army revolvers and forty-six horse artillery sabers.
  • 7th Battery: Nineteen Army revolvers and 143 horse artillery sabers.
  • 9th Battery: Fourteen Army revolvers and thirty horse artillery sabers.
  • 10th Battery: Twenty Navy revolvers and twenty horse artillery sabers.
  • 11th Battery: Twenty Army revolvers and twenty horse artillery sabers.

Other than the 7th Battery’s large number of sabers, all within reason!

Fortification Friday: Embrasures to protect the gunners

Over the last few weeks, we’ve looked at the placement of artillery in the field fortification, in what is called batteries.  The first option explored was a barbette mounting, where the cannon fired over the parapet.  Such an arrangement offered a wide field of fire.  But it also exposed the cannon crew to enemy fire.  Another alternative was to provide openings in the parapet through which the cannon could fire.  Thus allowing the gunners to remain behind the parapet as they worked the cannon. So let’s circle back to Mahan, who defined these openings along with introducing terms to describe the components:

The embrasure is an opening made in the parapet for a gun to fire through.  The bottom of the embrasure, termed the sole, is two feet nine inches, or four feet above the ground, on which the wheels of the carriage rest, according to the size of the gun; it slopes outward to allow the gun to be fired under an inclination, the base of this slope should never be less than six times the altitude….

I hate to interrupt the professor mid-sentence, but it is a run-on.  And we need to consider these components of the embrasure in turn.  Allow me to use the diagram from Mahan’s post-war instruction (which is somewhat cleaner for purposes of highlighting these parts of the embrasure):

MahanFig33

What we see here is two sub-diagrams depicting a section of the parapet on which an embrasure is placed.  On the right is the plan, or the fortification as seen from directly above, laid out across the horizontal plane.  On the left is the elevation, or vertical.  I’ll put a solid blue line between the two sub-diagrams for clarity, and indicate where the sole is located:

MahanFig33_Sole

On the right, the sole is C-D-I-K.  On the left, the sole is line a-b.  In simple terms, we might consider the sole to be the floor of the embrasure.  So the cannon will be firing over the sole.  Thus we have two properties to consider.

First is the height of the sole respective to what would be the tread of the banquette, or interior behind the parapet.  Mahan tells us “two feet, nine inches or four feet” depending on the size of the cannon. Recall that is the same measure specified when considering the height of the mound behind the parapet for barbette positions.  Yes, properties of the cannon and carriage remain the same, but we are applying those measures in different ways.  For a barbette, that specified the measure from the interior crest down to the mound of earth (and thus determined how high the mound of earth needed to be).  For a parapet, that specified the measure from the interior edge of the sole down to the tread. Another way to look at it, when building an embrasure the measure of two feet, nine inches (or four feet for the bigger gun) determines how deep the embrasure is cut into the parapet.  Regardless of barbette or embrasure, the cannon’s muzzle needed to have clearance to fire some 33 inches above the flat ground on which the carriage (wheels) sat. Got that?

The second property to consider is the horizontal lay of the sole as it extends through the parapet.  To allow declination, the sole had to slope down from the interior edge. So we have to think about how that opening is defined and regulated, as Mahan continued:

… the interior opening, termed the mouth, is from eighteen inches to two feet wide, according to the caliber of the gun, and is of a rectangular form….

Turning back to our diagram, here is the mouth:

MahanFig33_Mouth

On the right, that’s under I-K-O-P; to the left a triangle from a-d-unlabeled point.  This mouth was a foot-and-a-half to two feet wide.  The “gun books” tell us 6-pdr field gun muzzle swells are 8.25 inches in diameter.  The muzzle band on the 32-pdr field howitzer is 11 inches in diameter. Later models of the 24-pdr siege gun had a muzzle swell out to 15.5 inches. Going to the extreme end, 32-pdr and 42-pdr seacoast guns have muzzle swells to 15.5 inches and 17 inches, respectively.  So you can see where 24 inches (two feet) would give adequate clearance for the largest guns that could possibly be used in a field fortification… at the time Mahan was writing that is, as the big Parrotts and Rodmans were not yet in service.

From the mouth, the sole will decline outward as we noted above.  Furthermore, it should also expand wider to allow some traverse for the gun.  And the professor had a word for that widening of the sole:

… the embrasure widens toward the exterior, which widening is term the splay….

The splay is not necessarily a “part” but more so a specification applied to the embrasure.  But here’s where that specification would play out on the diagram:

MahanFig33_Splay

If I had fancy 3-D modeling, you’d have a cool animation spinning about to show how this splay opens outward.  Sorry, I don’t so you’ll have to go visit a fort for that.  But you get the idea of where the splay is employed.  But as with all parts of a fortification, the splay had natural limits, lest it be too great or too small… or grossly impact other components:

… the manner in which the splay is regulated, is by producing the sole to the exterior slope of the parapet, and making this exterior line measured on the sole, equal to half the distance between the inner and outer lines of the sole. This construction makes the sole a trapezoidal figure, the side of the trapezoid, on the interior being eighteen inches, or two feet; the opposite side being equal to or half the perpendicular distance between the two sides.

We fixed the mouth at between 18 and 24 inches.  To set the exterior opening’s size, take a measure from the mouth to the front (line C-D in the diagram, but not necessarily correlating to the front of the parapet mind you).  Half of that measure will give you the necessary width of the exterior opening.

So it is important to have a line defined that is perpendicular to the mouth, running directly out the embrasure.  What do we call that?

The line which bisects the sole is termed the directrix of the embrasure….

And we see that on the diagram:

MahanFig33_Dtrx

Since this is a 3-dimensional feature, the embrasure must have sides for the trapezoidal sole.  What are those called?

… the sides of the embrasure, termed the cheeks, are laid out by setting off two points on the exterior crest of the parapet, one on the right, the other on the left of the sole, so that the horizontal distance of these points from the sole shall be equal to one-third their height above it.  Lines are then drawn on the exterior slope, from these points to the exterior points of the sole; lines are in like manner drawn from the same points, on the superior slope to the upper points of the mouth, on the interior crest.  These four lines form the boundaries of the two cheeks on the superior and exterior slopes.

So let me highlight the cheeks on the diagram:

MahanFig33_cheek

Note how these cheeks are also sloped… maybe we include that as part of the splay… to allow better clearance.  What we are defining here with the embrasure is not only the opening that the cannon’s muzzle will use, but also the opening that the projectile will exit the fortification.  Thus it is rather important to provide ample clearance!

Having identified the components and some of the properties of embrasures, let’s take a step back and consider how these were used.  Yes, the gunners now had a parapet between them and the attackers. But as laid out between the cheeks and sole, the splay also limited the field of fire.  Thus embrasure placement was very important.  One might set the directrix to be perpendicular to the line of the parapet.  Or perhaps the situation required an off-set angle, or oblique, to best cover a particular corner of the works.  Thus embrasure construction was not simply digging out some “windows” for the fort.  As these embrasures would define what sectors the big guns could dominate, the engineer and artillerist had to work together in order to get the most out of the emplacement.  We’ll look at that in the next installment.

(Citations from Dennis Hart Mahan, A Treatise on Field Fortifications, New York: John Wiley, 1852, pages 54-5.)